The present invention relates to apparatus and method for applying tensioned elastic to material, and more specifically to apparatus and method for applying elongate tensioned elastic members transversely to a moving web of material.
The application of elongate tensioned elastic extending transversely of a moving flow path has been difficult to accomplish with previously known apparatus and methods. Many previously known devices and methods have used apparatus which requires that the apparatus stop, or slow down substantially, and then start, or speed up, again to permit transference of the elastic onto material. Other methods and equipment may include the application of non-tensioned material in a substantially continuous stream which then must be further acted upon, such as by heat activation or other process, to produce an elastic characteristic in the material. Yet others use apparatus and methods which may provide adequate operation for applying tape-like materials, but are less desirable for applying tensioned elastic strands.
A general object of the present invention is to provide novel apparatus which permits substantially continuous movement of elongate elastic from an elastic storage to final application on material, with the tensioned elastic extending transversely of the flow path of the material on which it is to be applied.
More specifically, an object of the invention is to provide apparatus in which material to have elastic applied thereto is carried in one direction along a flow path, and a conveyor extending transversely of the material flow path is operable to continuously draw elastic from storage, tension it and carry it into a position extending transversely of and spaced from the material flow path. A transfer conveyor movable generally in the direction of the flow path is operable to grip a section of the elastic extending transversely of the flow path, and a severing device is operable to sever the elastic outside the grip of the transfer conveyor allowing the transfer conveyor to carry a selected length of elastic into position to be deposited on the material. The transverse conveyor and the transfer conveyor are able to operate substantially continuously to produce substantially continuous material movement.
Another object of the present invention is to provide novel apparatus in which elongate tensioned elastic can be substantially continuously provided extending transversely of a moving web of material which may be used to produce a garment. The apparatus is suitable for application of elastic at high working speeds without the need for interruption or intermittent operation of the moving web of material used to produce the garment. It is especially well adapted for the application of the waist zone elastics to disposable diapers or similar products. A first conveyor is operable to carry garment material in one direction along a flow path. A second, or transverse, conveyor extends transversely of the flow path and is operable to draw an elongate section of elastic from an elastic storage, impart tension to the elastic, and carry it substantially continuously into a position extending transversely of and spaced from a web of material carried along the flow path. A pair of spaced apart transfer grippers are carried in the direction of the material flow path and are operable to grasp spaced portions of the elastic carried on the transverse conveyors. Substantially immediately after being grasped portions of the elastic outside the spaced transfer grippers are severed from remainder portions of the elastic held in the transverse conveyor, permitting the transfer grippers to carry stretched elastic extending transversely of the material path into a position to deposit it on the material web.
Another object of the invention is to provide a novel method for applying elongate tensioned elastic to material moving in one direction along a flow path with the elastic extending transversely of the flow path. The method includes the steps of drawing an elongate section of elastic from a quantity of elastic, stretching the section of elastic to a desired tension, moving the elastic in its tensioned state longitudinally and substantially continuously along a second flow path extending transversely of and spaced from the flow path for the material, grasping spaced apart portions of the section of elastic adjacent opposite sides of the flow path, and while maintaining tension in the elastic moving it in the direction of the material flow path, cutting the section of elastic outside the spaced portions to sever the elastic from remainder portions drawn from the elastic storage, and depositing the severed elastic while still in tension on material carried along the flow path.
These and other objects and advantages will become more apparent as the following description is read in conjunction with the drawings.